if_gre.c revision 1.49.2.1.2.2
1 /* $NetBSD: if_gre.c,v 1.49.2.1.2.2 2005/05/24 19:34:16 riz Exp $ */ 2 3 /* 4 * Copyright (c) 1998 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Heiko W.Rupp <hwr (at) pilhuhn.de> 9 * 10 * IPv6-over-GRE contributed by Gert Doering <gert (at) greenie.muc.de> 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the NetBSD 23 * Foundation, Inc. and its contributors. 24 * 4. Neither the name of The NetBSD Foundation nor the names of its 25 * contributors may be used to endorse or promote products derived 26 * from this software without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 29 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 30 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 31 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 32 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 33 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 34 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 35 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 36 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 37 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 38 * POSSIBILITY OF SUCH DAMAGE. 39 */ 40 41 /* 42 * Encapsulate L3 protocols into IP 43 * See RFC 1701 and 1702 for more details. 44 * If_gre is compatible with Cisco GRE tunnels, so you can 45 * have a NetBSD box as the other end of a tunnel interface of a Cisco 46 * router. See gre(4) for more details. 47 * Also supported: IP in IP encaps (proto 55) as of RFC 2004 48 */ 49 50 #include <sys/cdefs.h> 51 __KERNEL_RCSID(0, "$NetBSD: if_gre.c,v 1.49.2.1.2.2 2005/05/24 19:34:16 riz Exp $"); 52 53 #include "opt_inet.h" 54 #include "opt_ns.h" 55 #include "bpfilter.h" 56 57 #include <sys/param.h> 58 #include <sys/malloc.h> 59 #include <sys/mbuf.h> 60 #include <sys/proc.h> 61 #include <sys/protosw.h> 62 #include <sys/socket.h> 63 #include <sys/ioctl.h> 64 #include <sys/queue.h> 65 #if __NetBSD__ 66 #include <sys/systm.h> 67 #endif 68 69 #include <machine/cpu.h> 70 71 #include <net/ethertypes.h> 72 #include <net/if.h> 73 #include <net/if_types.h> 74 #include <net/netisr.h> 75 #include <net/route.h> 76 77 #ifdef INET 78 #include <netinet/in.h> 79 #include <netinet/in_systm.h> 80 #include <netinet/in_var.h> 81 #include <netinet/ip.h> 82 #include <netinet/ip_var.h> 83 #else 84 #error "Huh? if_gre without inet?" 85 #endif 86 87 #ifdef NS 88 #include <netns/ns.h> 89 #include <netns/ns_if.h> 90 #endif 91 92 #ifdef NETATALK 93 #include <netatalk/at.h> 94 #include <netatalk/at_var.h> 95 #include <netatalk/at_extern.h> 96 #endif 97 98 #if NBPFILTER > 0 99 #include <sys/time.h> 100 #include <net/bpf.h> 101 #endif 102 103 #include <net/if_gre.h> 104 105 /* 106 * It is not easy to calculate the right value for a GRE MTU. 107 * We leave this task to the admin and use the same default that 108 * other vendors use. 109 */ 110 #define GREMTU 1476 111 112 struct gre_softc_head gre_softc_list; 113 int ip_gre_ttl = GRE_TTL; 114 115 int gre_clone_create __P((struct if_clone *, int)); 116 void gre_clone_destroy __P((struct ifnet *)); 117 118 struct if_clone gre_cloner = 119 IF_CLONE_INITIALIZER("gre", gre_clone_create, gre_clone_destroy); 120 121 int gre_compute_route(struct gre_softc *sc); 122 123 void greattach __P((int)); 124 125 /* ARGSUSED */ 126 void 127 greattach(count) 128 int count; 129 { 130 131 LIST_INIT(&gre_softc_list); 132 if_clone_attach(&gre_cloner); 133 } 134 135 int 136 gre_clone_create(ifc, unit) 137 struct if_clone *ifc; 138 int unit; 139 { 140 struct gre_softc *sc; 141 142 sc = malloc(sizeof(struct gre_softc), M_DEVBUF, M_WAITOK); 143 memset(sc, 0, sizeof(struct gre_softc)); 144 145 sprintf(sc->sc_if.if_xname, "%s%d", ifc->ifc_name, unit); 146 sc->sc_if.if_softc = sc; 147 sc->sc_if.if_type = IFT_TUNNEL; 148 sc->sc_if.if_addrlen = 0; 149 sc->sc_if.if_hdrlen = 24; /* IP + GRE */ 150 sc->sc_if.if_dlt = DLT_NULL; 151 sc->sc_if.if_mtu = GREMTU; 152 sc->sc_if.if_flags = IFF_POINTOPOINT|IFF_MULTICAST; 153 sc->sc_if.if_output = gre_output; 154 sc->sc_if.if_ioctl = gre_ioctl; 155 sc->g_dst.s_addr = sc->g_src.s_addr = INADDR_ANY; 156 sc->g_proto = IPPROTO_GRE; 157 sc->sc_if.if_flags |= IFF_LINK0; 158 if_attach(&sc->sc_if); 159 if_alloc_sadl(&sc->sc_if); 160 #if NBPFILTER > 0 161 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int32_t)); 162 #endif 163 LIST_INSERT_HEAD(&gre_softc_list, sc, sc_list); 164 return (0); 165 } 166 167 void 168 gre_clone_destroy(ifp) 169 struct ifnet *ifp; 170 { 171 struct gre_softc *sc = ifp->if_softc; 172 173 LIST_REMOVE(sc, sc_list); 174 #if NBPFILTER > 0 175 bpfdetach(ifp); 176 #endif 177 if_detach(ifp); 178 free(sc, M_DEVBUF); 179 } 180 181 /* 182 * The output routine. Takes a packet and encapsulates it in the protocol 183 * given by sc->g_proto. See also RFC 1701 and RFC 2004 184 */ 185 int 186 gre_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 187 struct rtentry *rt) 188 { 189 int error = 0; 190 struct gre_softc *sc = ifp->if_softc; 191 struct greip *gh; 192 struct ip *ip; 193 u_int8_t ip_tos = 0; 194 u_int16_t etype = 0; 195 struct mobile_h mob_h; 196 197 if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == 0 || 198 sc->g_src.s_addr == INADDR_ANY || sc->g_dst.s_addr == INADDR_ANY) { 199 m_freem(m); 200 error = ENETDOWN; 201 goto end; 202 } 203 204 gh = NULL; 205 ip = NULL; 206 207 #if NBPFILTER >0 208 if (ifp->if_bpf) { 209 /* see comment of other if_foo.c files */ 210 struct mbuf m0; 211 u_int32_t af = dst->sa_family; 212 213 m0.m_next = m; 214 m0.m_len = 4; 215 m0.m_data = (char *)⁡ 216 217 bpf_mtap(ifp->if_bpf, &m0); 218 } 219 #endif 220 221 m->m_flags &= ~(M_BCAST|M_MCAST); 222 223 if (sc->g_proto == IPPROTO_MOBILE) { 224 if (dst->sa_family == AF_INET) { 225 struct mbuf *m0; 226 int msiz; 227 228 ip = mtod(m, struct ip *); 229 230 memset(&mob_h, 0, MOB_H_SIZ_L); 231 mob_h.proto = (ip->ip_p) << 8; 232 mob_h.odst = ip->ip_dst.s_addr; 233 ip->ip_dst.s_addr = sc->g_dst.s_addr; 234 235 /* 236 * If the packet comes from our host, we only change 237 * the destination address in the IP header. 238 * Else we also need to save and change the source 239 */ 240 if (in_hosteq(ip->ip_src, sc->g_src)) { 241 msiz = MOB_H_SIZ_S; 242 } else { 243 mob_h.proto |= MOB_H_SBIT; 244 mob_h.osrc = ip->ip_src.s_addr; 245 ip->ip_src.s_addr = sc->g_src.s_addr; 246 msiz = MOB_H_SIZ_L; 247 } 248 HTONS(mob_h.proto); 249 mob_h.hcrc = gre_in_cksum((u_int16_t *)&mob_h, msiz); 250 251 if ((m->m_data - msiz) < m->m_pktdat) { 252 /* need new mbuf */ 253 MGETHDR(m0, M_DONTWAIT, MT_HEADER); 254 if (m0 == NULL) { 255 IF_DROP(&ifp->if_snd); 256 m_freem(m); 257 error = ENOBUFS; 258 goto end; 259 } 260 m0->m_next = m; 261 m->m_data += sizeof(struct ip); 262 m->m_len -= sizeof(struct ip); 263 m0->m_pkthdr.len = m->m_pkthdr.len + msiz; 264 m0->m_len = msiz + sizeof(struct ip); 265 m0->m_data += max_linkhdr; 266 memcpy(mtod(m0, caddr_t), (caddr_t)ip, 267 sizeof(struct ip)); 268 m = m0; 269 } else { /* we have some space left in the old one */ 270 m->m_data -= msiz; 271 m->m_len += msiz; 272 m->m_pkthdr.len += msiz; 273 memmove(mtod(m, caddr_t), ip, 274 sizeof(struct ip)); 275 } 276 ip = mtod(m, struct ip *); 277 memcpy((caddr_t)(ip + 1), &mob_h, (unsigned)msiz); 278 ip->ip_len = htons(ntohs(ip->ip_len) + msiz); 279 } else { /* AF_INET */ 280 IF_DROP(&ifp->if_snd); 281 m_freem(m); 282 error = EINVAL; 283 goto end; 284 } 285 } else if (sc->g_proto == IPPROTO_GRE) { 286 #ifdef GRE_DEBUG 287 printf( "start gre_output/GRE, dst->sa_family=%d\n", 288 dst->sa_family ); 289 #endif 290 switch (dst->sa_family) { 291 case AF_INET: 292 ip = mtod(m, struct ip *); 293 ip_tos = ip->ip_tos; 294 etype = ETHERTYPE_IP; 295 break; 296 #ifdef NETATALK 297 case AF_APPLETALK: 298 etype = ETHERTYPE_ATALK; 299 break; 300 #endif 301 #ifdef NS 302 case AF_NS: 303 etype = ETHERTYPE_NS; 304 break; 305 #endif 306 #ifdef INET6 307 case AF_INET6: 308 etype = ETHERTYPE_IPV6; 309 break; 310 #endif 311 default: 312 IF_DROP(&ifp->if_snd); 313 m_freem(m); 314 error = EAFNOSUPPORT; 315 goto end; 316 } 317 M_PREPEND(m, sizeof(struct greip), M_DONTWAIT); 318 } else { 319 IF_DROP(&ifp->if_snd); 320 m_freem(m); 321 error = EINVAL; 322 goto end; 323 } 324 325 if (m == NULL) { /* impossible */ 326 IF_DROP(&ifp->if_snd); 327 error = ENOBUFS; 328 goto end; 329 } 330 331 gh = mtod(m, struct greip *); 332 if (sc->g_proto == IPPROTO_GRE) { 333 /* we don't have any GRE flags for now */ 334 335 memset((void *)&gh->gi_g, 0, sizeof(struct gre_h)); 336 gh->gi_ptype = htons(etype); 337 } 338 339 gh->gi_pr = sc->g_proto; 340 if (sc->g_proto != IPPROTO_MOBILE) { 341 gh->gi_src = sc->g_src; 342 gh->gi_dst = sc->g_dst; 343 ((struct ip*)gh)->ip_hl = (sizeof(struct ip)) >> 2; 344 ((struct ip*)gh)->ip_ttl = ip_gre_ttl; 345 ((struct ip*)gh)->ip_tos = ip_tos; 346 gh->gi_len = htons(m->m_pkthdr.len); 347 } 348 349 ifp->if_opackets++; 350 ifp->if_obytes += m->m_pkthdr.len; 351 /* send it off */ 352 error = ip_output(m, NULL, &sc->route, 0, 353 (struct ip_moptions *)NULL, (struct socket *)NULL); 354 end: 355 if (error) 356 ifp->if_oerrors++; 357 return (error); 358 } 359 360 int 361 gre_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 362 { 363 struct proc *p = curproc; /* XXX */ 364 struct ifreq *ifr = (struct ifreq *)data; 365 struct if_laddrreq *lifr = (struct if_laddrreq *)data; 366 struct gre_softc *sc = ifp->if_softc; 367 int s; 368 struct sockaddr_in si; 369 struct sockaddr *sa = NULL; 370 int error; 371 372 error = 0; 373 374 s = splnet(); 375 switch (cmd) { 376 case SIOCSIFADDR: 377 ifp->if_flags |= IFF_UP; 378 break; 379 case SIOCSIFDSTADDR: 380 break; 381 case SIOCSIFFLAGS: 382 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 383 break; 384 if ((ifr->ifr_flags & IFF_LINK0) != 0) 385 sc->g_proto = IPPROTO_GRE; 386 else 387 sc->g_proto = IPPROTO_MOBILE; 388 break; 389 case SIOCSIFMTU: 390 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 391 break; 392 if (ifr->ifr_mtu < 576) { 393 error = EINVAL; 394 break; 395 } 396 ifp->if_mtu = ifr->ifr_mtu; 397 break; 398 case SIOCGIFMTU: 399 ifr->ifr_mtu = sc->sc_if.if_mtu; 400 break; 401 case SIOCADDMULTI: 402 case SIOCDELMULTI: 403 if (ifr == 0) { 404 error = EAFNOSUPPORT; 405 break; 406 } 407 switch (ifr->ifr_addr.sa_family) { 408 #ifdef INET 409 case AF_INET: 410 break; 411 #endif 412 #ifdef INET6 413 case AF_INET6: 414 break; 415 #endif 416 default: 417 error = EAFNOSUPPORT; 418 break; 419 } 420 break; 421 case GRESPROTO: 422 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 423 break; 424 sc->g_proto = ifr->ifr_flags; 425 switch (sc->g_proto) { 426 case IPPROTO_GRE: 427 ifp->if_flags |= IFF_LINK0; 428 break; 429 case IPPROTO_MOBILE: 430 ifp->if_flags &= ~IFF_LINK0; 431 break; 432 default: 433 error = EPROTONOSUPPORT; 434 break; 435 } 436 break; 437 case GREGPROTO: 438 ifr->ifr_flags = sc->g_proto; 439 break; 440 case GRESADDRS: 441 case GRESADDRD: 442 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 443 break; 444 /* 445 * set tunnel endpoints, compute a less specific route 446 * to the remote end and mark if as up 447 */ 448 sa = &ifr->ifr_addr; 449 if (cmd == GRESADDRS) 450 sc->g_src = (satosin(sa))->sin_addr; 451 if (cmd == GRESADDRD) 452 sc->g_dst = (satosin(sa))->sin_addr; 453 recompute: 454 if ((sc->g_src.s_addr != INADDR_ANY) && 455 (sc->g_dst.s_addr != INADDR_ANY)) { 456 if (sc->route.ro_rt != 0) /* free old route */ 457 RTFREE(sc->route.ro_rt); 458 if (gre_compute_route(sc) == 0) 459 ifp->if_flags |= IFF_RUNNING; 460 else 461 ifp->if_flags &= ~IFF_RUNNING; 462 } 463 break; 464 case GREGADDRS: 465 memset(&si, 0, sizeof(si)); 466 si.sin_family = AF_INET; 467 si.sin_len = sizeof(struct sockaddr_in); 468 si.sin_addr.s_addr = sc->g_src.s_addr; 469 sa = sintosa(&si); 470 ifr->ifr_addr = *sa; 471 break; 472 case GREGADDRD: 473 memset(&si, 0, sizeof(si)); 474 si.sin_family = AF_INET; 475 si.sin_len = sizeof(struct sockaddr_in); 476 si.sin_addr.s_addr = sc->g_dst.s_addr; 477 sa = sintosa(&si); 478 ifr->ifr_addr = *sa; 479 break; 480 case SIOCSLIFPHYADDR: 481 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 482 break; 483 if (lifr->addr.ss_family != AF_INET || 484 lifr->dstaddr.ss_family != AF_INET) { 485 error = EAFNOSUPPORT; 486 break; 487 } 488 if (lifr->addr.ss_len != sizeof(si) || 489 lifr->dstaddr.ss_len != sizeof(si)) { 490 error = EINVAL; 491 break; 492 } 493 sc->g_src = (satosin((struct sockadrr *)&lifr->addr))->sin_addr; 494 sc->g_dst = 495 (satosin((struct sockadrr *)&lifr->dstaddr))->sin_addr; 496 goto recompute; 497 case SIOCDIFPHYADDR: 498 if ((error = suser(p->p_ucred, &p->p_acflag)) != 0) 499 break; 500 sc->g_src.s_addr = INADDR_ANY; 501 sc->g_dst.s_addr = INADDR_ANY; 502 break; 503 case SIOCGLIFPHYADDR: 504 if (sc->g_src.s_addr == INADDR_ANY || 505 sc->g_dst.s_addr == INADDR_ANY) { 506 error = EADDRNOTAVAIL; 507 break; 508 } 509 memset(&si, 0, sizeof(si)); 510 si.sin_family = AF_INET; 511 si.sin_len = sizeof(struct sockaddr_in); 512 si.sin_addr.s_addr = sc->g_src.s_addr; 513 memcpy(&lifr->addr, &si, sizeof(si)); 514 si.sin_addr.s_addr = sc->g_dst.s_addr; 515 memcpy(&lifr->dstaddr, &si, sizeof(si)); 516 break; 517 default: 518 error = EINVAL; 519 break; 520 } 521 522 splx(s); 523 return (error); 524 } 525 526 /* 527 * computes a route to our destination that is not the one 528 * which would be taken by ip_output(), as this one will loop back to 529 * us. If the interface is p2p as a--->b, then a routing entry exists 530 * If we now send a packet to b (e.g. ping b), this will come down here 531 * gets src=a, dst=b tacked on and would from ip_output() sent back to 532 * if_gre. 533 * Goal here is to compute a route to b that is less specific than 534 * a-->b. We know that this one exists as in normal operation we have 535 * at least a default route which matches. 536 */ 537 int 538 gre_compute_route(struct gre_softc *sc) 539 { 540 struct route *ro; 541 u_int32_t a, b, c; 542 543 ro = &sc->route; 544 545 memset(ro, 0, sizeof(struct route)); 546 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 547 ro->ro_dst.sa_family = AF_INET; 548 ro->ro_dst.sa_len = sizeof(ro->ro_dst); 549 550 /* 551 * toggle last bit, so our interface is not found, but a less 552 * specific route. I'd rather like to specify a shorter mask, 553 * but this is not possible. Should work though. XXX 554 * there is a simpler way ... 555 */ 556 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) { 557 a = ntohl(sc->g_dst.s_addr); 558 b = a & 0x01; 559 c = a & 0xfffffffe; 560 b = b ^ 0x01; 561 a = b | c; 562 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr.s_addr 563 = htonl(a); 564 } 565 566 #ifdef DIAGNOSTIC 567 printf("%s: searching for a route to %s", sc->sc_if.if_xname, 568 inet_ntoa(((struct sockaddr_in *)&ro->ro_dst)->sin_addr)); 569 #endif 570 571 rtalloc(ro); 572 573 /* 574 * check if this returned a route at all and this route is no 575 * recursion to ourself 576 */ 577 if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp->if_softc == sc) { 578 #ifdef DIAGNOSTIC 579 if (ro->ro_rt == NULL) 580 printf(" - no route found!\n"); 581 else 582 printf(" - route loops back to ourself!\n"); 583 #endif 584 return EADDRNOTAVAIL; 585 } 586 587 /* 588 * now change it back - else ip_output will just drop 589 * the route and search one to this interface ... 590 */ 591 if ((sc->sc_if.if_flags & IFF_LINK1) == 0) 592 ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = sc->g_dst; 593 594 #ifdef DIAGNOSTIC 595 printf(", choosing %s with gateway %s", ro->ro_rt->rt_ifp->if_xname, 596 inet_ntoa(((struct sockaddr_in *)(ro->ro_rt->rt_gateway))->sin_addr)); 597 printf("\n"); 598 #endif 599 600 return 0; 601 } 602 603 /* 604 * do a checksum of a buffer - much like in_cksum, which operates on 605 * mbufs. 606 */ 607 u_int16_t 608 gre_in_cksum(u_int16_t *p, u_int len) 609 { 610 u_int32_t sum = 0; 611 int nwords = len >> 1; 612 613 while (nwords-- != 0) 614 sum += *p++; 615 616 if (len & 1) { 617 union { 618 u_short w; 619 u_char c[2]; 620 } u; 621 u.c[0] = *(u_char *)p; 622 u.c[1] = 0; 623 sum += u.w; 624 } 625 626 /* end-around-carry */ 627 sum = (sum >> 16) + (sum & 0xffff); 628 sum += (sum >> 16); 629 return (~sum); 630 } 631
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